A 68-year-old female presented with chest pain and breathlessness. She had breast carcinoma treated 17 years ago, with further surgical excision for recurrence 7 years ago. Computerised tomography (CT) demonstrated bi-lateral pulmonary embolism, with extensive lymphadenopathy and lung metastases. She was treated with therapeutic heparin. Echocardiography revealed a right ventricular mass attached to the tricuspid valve chordae (Fig. 1; Videos 1 and 2), which could be thrombus, marantic or infective vegetation. Blood cultures were negative. Lymph node biopsy showed malignant cells, likely of breast origin. Despite therapeutic anti-coagulation, echocardiogram 3 weeks after initial presentation demonstrated enlargement of the original mass and an additional mass (Fig. 1; Videos 3 and 4), implying that these were most probably marantic. We retrospectively reviewed the CT performed at first presentation, which also demonstrated the original right ventricular mass (Fig. 1). She died from recurrent embolic cerebrovascular events, confirmed on MRI, within a month from initial presentation. In advanced stages of malignancy, marantic endocarditis or non-bacterial thrombotic endocarditis can develop in hypercoagulable states. It has a rapidly progressive course, with embolisation of vegetations to other organs. The sterile vegetations consist of fibrin and platelets (1, 2). Patients should be anti-coagulated. In terminal cases, surgery rarely alters the final outcome (2, 3). Figure 1 (A and B) Right ventricular mass (arrowed) attached to the tricuspid valve chordae apparatus on echocardiography, in apical four-chamber view, and modified parasternal right ventricular inflow view respectively; (C and D) repeat echocardiogram demonstrating ... Video 1 The initial right ventricular mass attached to the tricuspid valve chordae apparatus on echocardiography, in modified parasternal right ventricular inflow view. Download Video 1 via http://dx.doi.org/10.1530/ERP-14-0066-v1 Download Video 1 Video 2 The initial right ventricular mass attached to the tricuspid valve chordae apparatus on echocardiography, in apical four-chamber view. Download Video 2 via http://dx.doi.org/10.1530/ERP-14-0066-v2 Download Video 2 Video 3 Repeat echocardiogram demonstrating enlargement of the original mass and an additional mass, in modified parasternal right ventricular inflow view. Download Video 3 via http://dx.doi.org/10.1530/ERP-14-0066-v3 Download Video 3 Video 4 Repeat echocardiogram demonstrating enlargement of the original mass and an additional mass, in apical four-chamber view. Download Video 4 via http://dx.doi.org/10.1530/ERP-14-0066-v4 Download Video 4